This invention concerns a joint locked in place between the smooth end of a first tubular element and the socket end of a second tubular element, of the type comprising a sealing gasket housed in the socket, a locking ring incorporating inner teeth surrounding the smooth end, and a counter-flange fitted with means for attachment to the socket and configured to implement position-retention of the locking ring preventing backward movement. The invention is especially applicable to the installation of systems of pipes made of ductile cast iron.
Whatever the type of gasket used, whether a radial compression gasket for joints termed "automatic", or an axial compression gasket for joints termed "mechanical", locked joints of this type must restrict the backward movement of the smooth pipe end to a very low value during pressurization of the pipe system, while being easy to use.
Furthermore, to ensure that the tubular joint can be locked in an effective, durable manner and to ensure that the life of the tubular elements or pipes is not affected, the areas of contact between the locking ring and the metal parts enclosing it should be protected against corrosion.